I can see reasons for them not doing this. One would be that they probably don't know. When the pools are looking for a block, they are, I believe, looking at many differnt combinations of transactions at the same time across their supporting miners.
I suppose they are using many different combinations. That doesn't really matter for most people because in the combinations, they're probably swapping out low-priority transactions (with low fees) because they really want to maximize the fees they get.Another, they don't know what they will use next until they see what was used by the successfully found blocks.
What? This is only for the next block, the transactions in the block that they are trying to mine.they don't do that because:
Offer it as a paid service. People pay for Level 2 quotes I am sure merchants would pay for "pool visibility".- it's going to cause extra server load from thousands of people refreshing every 30 seconds to see whether their 0.0001 BTC no fee transaction went through
- it's extra work that does not benefit their customers (miners)
- it doesn't generate revenue
Yes. Merchants would pay a few bitcents per block to see what transactions will be included. Then they'll know with a pretty high degree of certainty if someone even attempted a double-spend. If merchants could see this for the mining pools compromising ~80-90% of the hashing power of the network, then they could even accept payments with even 0 confirmations, because for a conflicting transaction to be mined (the main worry for merchants) would require most of the solo-miners (comprising ~15% of the network) to collude and include the conflicting transaction. Since I'm pretty sure that the non-pool 15% is pretty fragmented (no one person has control of more than 0.5% of the network), you'd need to get a lot of solo miners to include the conflicting transaction.
